Yesterday I posted a Google Trends chart showing relative search volume for "BBM for iPhone" and "BBM for Android", the hypothesis being that RIM user who switched platforms would look for BBM on their new phone (though it doesn't exist).

Narrowing this into the USA is equally interesting: it looks like rather more Blackberry users went to iPhone than Android, and also that they've now mostly already left (borne out by most other market stats). "BBM for iPhone" is red, "BBM for Android" is blue.

This speaks to the question of whether the RIM strategy of offering Android apps on BB10 (sort of) will work: the overlap between iPhone and Android app availability is far from perfect.